JPH08210215A - Fuel injection valve for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To clearly regulate a preliminary stroke and a residual stroke when high rotational speeds and full load are applied so as to separate both strokes by acting pressure generated in a damping space on the opening stroke of the valve member, against the opening stroke of a valve member on the residual stroke of the valve member, in the damping space. SOLUTION: A damping space 63, in which fuel is filled, is disposed in a fuel injection valve and is restricted by an end surface 41 of a valve member 11, whose diameter is larger than that of a part 61 of a nozzle spindle 39 and an end surface 65 formed on a lower side of an intermediate disk 3 faced to a valve member 11 side. In the damping space 63, pressure generated in the damping space 63 on the opening stroke of the valve member 11 acts against the opening stroke of the valve member 11 on a residual stroke of the valve member 11. The preliminary stroke and the residual stroke are clearly regulated in the case of high rotational speeds and full load, and both strokes are separated from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for an internal combustion engine, which has a valve member slidable in the axial direction,
The valve member is guided in the guide hole of the valve body, and the valve body is clamped to the valve holding body via the intermediate disc, and the two inside the valve holding body act on the valve member in the closing direction. A chamber is provided for receiving the valve spring, the first of the two valve springs always acting on the valve member via the nozzle spindle, whereas the second valve spring is A front stroke which acts on the valve member after the end of a predetermined opening stroke of the valve member forming a front stroke, whereby the opening movement of the valve member opposes the spring force of the first valve spring;
And a remaining stroke against the spring force of the first and second valve springs.

[0002]

2. Description of the Prior Art European Patent No. 2 of this type
In the fuel injection valve known from U.S. Pat. No. 82,489, a piston-shaped valve member is axially guided in a bore of a valve body and has a conical sealing surface at one end,
The conical sealing surface allows the valve member to cooperate with the valve seat formed in the valve body by the reduced diameter portion of the hole (where the diameter is reduced). Is
An injection opening is provided in the combustion chamber of the internal combustion engine to be supplied. The valve member is loaded by a nozzle spindle opposite the sealing surface, which nozzle spindle is guided in an intermediate disc connected to the valve disc and in a valve retainer axially clamped to the intermediate disc. Has been done. In this case, the valve holding body is, in the known fuel injection valve,
It is configured as a twin spring holder, for which two valve springs are arranged one behind the other in a chamber formed inside the valve holder, these valve springs being arranged via a spring bearing. It acts on the nozzle spindle and also on the valve member.

At this time, non-work is performed in order to perform the opening stroke of the valve member, which is convenient for vaporizing the fuel in the combustion chamber of the internal combustion engine, in two stages having a short stagnation time (or transition time). In the position, that is to say with the injection valve closed, only the first valve spring abuts the nozzle spindle which holds the valve member against the valve seat.

The second valve spring first comes into contact with the nozzle spindle after a predetermined opening stroke (previous stroke) of the valve member, whereby the closing force against the opening force is applied to the second stage (remaining stroke) of the opening stroke. Stroke). In this case, the opening stroke movement of the valve member is obtained by the constantly rising fuel pressure acting on the annular shoulder of the valve member. This fuel pressure first overcomes the spring force of the first spring and lifts the valve member from its valve seat. After the end of the previous stroke and after the spring force of the second valve spring acts, the fuel pressure causes the valve member to continuously slide further against the spring force of the two valve springs for a short time. Is no longer sufficient, the valve member is held in its stroke position for a short time. After an adjustable predetermined fuel pressure is obtained via the preload of the second spring, the valve member is again displaced against the spring force of the two valve springs until it abuts the stopper. Do the rest of the stroke exercise.

However, in this case, the known fuel injection valve has a high rotational speed or a high load (a large amount of fuel injection).
At, the fuel pressure loading the valve member and thus the opening stroke speed of the valve member increases rapidly enough that there is no stagnation between the previous stroke and the rest of the stroke, so that the opening cross section at the injection opening is very high. It has the disadvantage that it is quickly and completely controlled to open, which adversely affects the vaporization of the fuel injected into the combustion chamber of the internal combustion engine.

Therefore, it is impossible for the known fuel injection valve to obtain the above-described injection progress even at a high rotational speed or a high load.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to avoid the above-mentioned drawbacks of the conventional fuel injection valve.

[0008]

According to the fuel injection valve of the present invention which has solved this problem, the valve member at least indirectly limits the buffer chamber filled with the fuel. The chamber is adapted such that during the opening stroke of the valve member the pressure created in the buffer chamber acts against the opening stroke of the valve member during the rest of the stroke of the valve member.

[0009]

The fuel injection valve of the present invention has the advantage that the front stroke and the remaining stroke can be clearly defined and separated from each other even at a high rotational speed and a high load (full load range). are doing.

Such an advantage is obtained by providing a buffer chamber which is at least indirectly limited by the valve member. The pressure of the opening stroke movement of the valve member formed in this buffer chamber acts against it during the rest of the stroke, whereas it closes so that the front stroke remains unbuffered in a known manner. Controlled. Since the valve member or the nozzle spindle directly forms the movable wall of the buffer chamber, the stroke speed of the valve member, which is based on the number of rotations or the load, is a direct control value for the degree of buffering. Therefore, the cushioning force that assists the spring force of the valve spring increases as the stroke speed of the valve member increases, especially during the remaining stroke, and a desired injection course is obtained at high rotation speed and high load.

In this case, in order to ensure a cushioning action as the second valve spring begins to take effect,
Particularly preferably, the damping chamber is controlled to be closed after the end of the front stroke of the valve member.

For this purpose, it is also possible to close the buffer chamber at the same time as the start of the opening stroke movement, in particular when performing a very small front stroke, via a small flow passage which forms a throttle. In this case, the stroke of the valve member until the effective buffer pressure is formed in the buffer chamber corresponds to the non-buffered front stroke of the valve member. The size of this small unstroked front stroke is advantageously adjusted by the size of the cross-section of the flow-through passage between the buffer chamber and the pressure relief chamber or the volume to be compressed in the buffer chamber.
In this case, the buffer pressure formation speed also depends largely on the stroke speed of the valve member, so that at high pressures a very short unbuffered front stroke of the valve member is obtained. By providing a storage chamber connected to the buffer chamber, the buffer pressure formation can be further controlled.

The flow-through passage connecting the buffer chamber, which is preferably formed between the valve body and the intermediate disc, to the pressure relief chamber, preferably the chamber for receiving the valve spring, is in a favorable manner an intermediate disc. It is formed in a nozzle spindle guided inside and frictionally connected to the valve member. The through-flow passage can be configured as an axial groove or a grinding section on the peripheral surface or as a vertical hole in the nozzle spindle. In this case, a control edge is provided in each case, via which the flow passage can be controlled by the valve element after the end of the front stroke. Such a closing control of the through-flow passage is obtained in an advantageous manner by the opening of the through-flow passage, which opens into the buffer chamber, into the bore of the intermediate disc.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the embodiments shown in the drawings.

The fuel injection valve for an internal combustion engine shown in FIG. 1 has a valve body 1, and this valve body 1 cooperates with an intermediate disk 3 that abuts on one end face side of the valve body 1. It is fastened to the valve holder 7 by the nozzle nut 5. The valve body 1 projects into a combustion chamber (not shown) of an internal combustion engine at an end portion of the valve body 1 on the side opposite to the intermediate disk 3, and the valve body 1 has a guide hole 9. In this guide hole 9, the piston-shaped valve member 1
1 is slidably guided in the axial direction, and this valve member 11 has a conical sealing surface 13 on one end surface side, by which the valve member 11
It cooperates with a valve seat 15 formed by reducing the diameter of the guide hole 9. In this case, the valve seat 15 is arranged at the end of the valve body 1 on the combustion chamber side, and limits the injection opening 17 provided at the end of the guide hole 9. This injection opening 1
7 continues to the downstream side of the valve seat 15 in the fuel injection direction.
The guide hole 9 of the valve member 11 is expanded in a known manner in one place to form a pressure chamber 19, in the region of which the valve member 11 has a pressure shoulder 21. The pressure chamber 19 communicates with a connection sleeve 27 provided in the valve holder 7 via an inflow passage 25 having a filter 23. A fuel feed line (not shown) extending from the fuel pressure pump is connected to the connecting sleeve 27. On the other side, the pressure chamber 19 is connected in a known manner to the valve seat surface 15 or the injection opening 17 via an annular gap between the shaft of the valve member 11 and the wall of the guide hole 9.

A chamber 29 for receiving a valve spring acting on the valve member 11 in the closing direction is provided in the valve holder 7 which is designed as two spring holders. In this case, a first valve spring 33 is arranged in the first spring chamber 31, which valve spring 33 is located on the side opposite to the intermediate disc 3 in the chamber 2.
It is fixedly supported at the end of 9 or at the bottom 35 of the first spring chamber 31 and, on the other hand, at the nozzle spindle 39 via a spring receiver 37. The other end of the nozzle spindle 39 is in contact with the end surface side 41 of the valve member 11 facing the side opposite to the sealing surface 13 and always acts on the valve member 11. First spring chamber 3
1 is followed by a second spring chamber 43 in the chamber 29 in the direction towards the intermediate disc 3, which is separated from the first spring chamber 31 by a disc 45. Has been. The disc 45 is a sleeve 47 that forms an annular step portion fixed to the casing in a direction toward the first spring chamber 31.
(The sleeve 47 also surrounds the first spring chamber 31), whereby the disc 45 is
It is in stationary contact with a second valve spring 49, which is supported by a disc 45 in the second spring chamber 43. This second valve spring 4
9 encloses a nozzle spindle 39 which is guided through a hole formed in the disc 45. The second valve spring 49 has an end portion on the valve member side supported by a disc-shaped pressing member 51, and an end portion on the other side abuts on an upper end surface 53 of the intermediate disc 3. The spindle shaft of the nozzle spindle 39 is slidably guided through the valve spring 49. The nozzle spindle 39 has an annular step 57 in the region of a through part that passes through a stepped hole 55 formed in the intermediate disk 3.
This annular step 57 slides in the spring chamber 43 in the axial direction during the opening stroke of the valve member 11, that is, when the valve member 11 leaves the intermediate disc 3 for a predetermined front stroke H1. It abuts on the movable pressure member 51.

The nozzle spindle 39 preferably consists of two parts, the first part 59 of which is the spring bearing 3.
7 to the annular step 57, the second part 61
Between the annular step 57 and the end face side 41 of the valve member 11 is formed by a cylindrical connecting member having a small diameter guided in the part of the stepped hole.

Further according to the invention, the fuel injection valve is provided with a buffer chamber 63 filled with fuel, which buffer chamber 63 is larger than the diameter of the second part 61 of the nozzle spindle 39. The end surface 41 of the valve member 11 and the valve member 11
Bounded by the lower end face 65 of the intermediate disc 3 which is directed to the side. The structure of the buffer chamber 63 is shown in FIG.
~ Is described in detail in FIG.

FIG. 2 shows a first embodiment, in which the buffer chamber 63 forms a flow path leading from the buffer chamber 63 to the chamber 29, the nozzle spindle 39.
Is controlled to be opened or closed via the axial groove and the radial groove formed in the second portion 61 of the.

Moreover, the second portion 61 of the nozzle spindle 39 has, on its outer peripheral surface, an axial groove 67 extending from the end surface side facing the annular step portion 57 side. The second portion 61 opens into an annular groove 69 provided at the end closer to the valve member, and the shaft of the second portion 61 of the nozzle spindle 39 continues in the direction towards the valve member 11. . The buffer chamber 6 is in the closed position of the valve member 11.
The width of the annular groove 69 protruding into the inside of the 3 is
The wall 71 of the stepped hole 55 closes the annular groove 69 because the edge 71 closer to the valve member is configured to pass through the lower end face 65 of the intermediate disc 3 after a predetermined opening stroke. Then, the connection between the buffer chamber 63 and the fuel-filled chamber 29 is controlled to be closed. At this time, the unbuffered stroke corresponding to the front stroke is preferably the front stroke H.
1, the annular step portion 57 has the same size as the pressure member 51.
The second valve spring 49 is effective until it comes into contact with.

In this case, in order to prevent the edge 71 from hitting or tilting the end face 65 and adversely affecting the operation, the entrance of the stepped hole 55 into the end face 65 of the intermediate disk 3 is prevented. The edge 71 and the corresponding annular edge in the section
It has a chamfer. This chamfer ensures that the second part 61 of the nozzle spindle 39 reliably penetrates into the stepped hole 55.

The maximum opening stroke H3 of the valve member 11 is
In all alternative embodiments, the end face 41 of the valve member 11 is restricted by abutting against the lower end face 65 of the intermediate disc 3.

The second embodiment shown in FIG. 3 differs from that of the first embodiment in that a flow-through passage between the buffer chamber 63 and the chamber 29 is formed in the second part 61 of the nozzle spindle. Is formed by an axially extending longitudinal hole 73 which is traversed by two lateral holes. In this case, the upper first lateral hole 75
Always opens into the part of the stepped hole 55 that receives the annular projection 57, which part of the chamber 2 via the gap between the nozzle spindle 39 and the pressure member 51.
It is arranged so as to be connected to 9. The second lower lateral hole 77 opens into the buffer chamber 63 at the closed position of the valve member 11, and after the front stroke H1 of the valve member 11 has passed, that is, the annular projection 57 abuts on the pressure member 51. Then hole 5
It is arranged to be closed by a wall of 5, with the annular edge at the inlet opening of the bore 55 and the lower edge of the lower transverse bore 77 forming a cooperating edge. . In this case, via the axial position of the lower lateral hole 77, the closing control time of the buffer chamber 63 can be adjusted to the respective needs.

In the third embodiment shown in FIG. 4, the flow passage between the buffer chamber 63 and the chamber 29 has a wall of a hole 55 formed in the intermediate disc 3 and a second passage of the nozzle spindle 39. It is formed via an annular gap 79 between the outer peripheral surface of the portion 61. Depending on the extent of the annular gap 79, the throttle action in the annular gap 79 can be adjusted via the stroke speed of the valve member 11. By this diaphragm action,
The through passage is controlled to be closed from a predetermined pressure in the buffer chamber 63. In this case, the time for forming this pressure corresponds to the unbuffered front stroke of the valve member 11.

The start of the action of the throttle in the annular gap 79 can also be adjusted by the structure of the buffer chamber 63. The buffer chamber 63 can be expanded by an additional storage chamber 81, as shown in FIG. This storage chamber 81 can advantageously be designed as a blind hole provided in the valve body 1 and / or in the intermediate disc 3.

The fuel injection valve according to the invention operates in the following manner.

In the non-working position, the valve member 11 is in the first position.
Since the sealing surface 13 is held in contact with the valve seat 15 by the spring force of the valve spring 33, the injection valve is closed.

With the start of fuel pressure pumping in the fuel injection pump, the pressure chamber 19 is loaded with high fuel pressure through the inflow passage 25, and the pressure in the pressure chamber 19 is raised by this high fuel pressure. This increase in pressure acts on the valve member 11 and lifts it from the valve seat 15 against the spring force of the valve spring 33 in a known manner. At this time, the limited pre-injection is injected into the combustion chamber of the internal combustion engine. The front stroke H1 of this valve member 11, which forms the first stage of the injection, ends when the annular projection 57 provided on the nozzle spindle 39 abuts the pressure member 51, in which case the valve member 11 Stays in this position. Because, the fuel pressure that constantly rises in the pressure chamber 19 is
This is because the value must exceed the spring force of 3,49. Advantageously, the pressure member 51 has an annular projection 57.
At the same time as (or immediately before) the contact with the buffer chamber 63
Since it is also closed, a pressure against the front stroke of the valve member 11 is formed in the buffer chamber 63 at the opening stroke of the valve member together with the spring force of the two valve springs 33 and 49. Especially in the third embodiment, this pressure formation is based on the stroke speed of the valve member 11 and is always proportional to the stroke speed of the valve member. Therefore, when the rotational speed and load of the internal combustion engine are high, a large buffer force is exerted. Is obtained.

At the end of the remaining cushioned stroke forming the second stage of the injection process, the end face 4 of the valve member 11
1 reaches the intermediate disk 3, and at this time, the end surface 41 of the valve member 11
The spacing between the lower end surface 65 of the intermediate disc 3 defines the maximum opening stroke H3. In this position, the valve member 11
Is fixed until the end of the injection process. The injection process ends when the pressure in the pressure chamber 19 drops, and the valve member is then replaced by the valve springs 33, 49.
Is brought into contact with.

The pressure in the buffer chamber 63 is released to the chamber 29 via the respective throughflow passages provided in the second portion 61 of the nozzle spindle 39, and the excess fuel is discharged from this chamber 29 at this time. Derivable via the return line.

As a result, according to the fuel injection valve of the present invention, the injection process can be carried out in two stages even at a high rotational speed and a high load, and each is provided on the intermediate disc 3 having a simple structure. Buffer chamber 63 and nozzle spindle 39
Due to the closable throughflow passages provided in the, the initial structural dimensions of the injection valve can be maintained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an injection valve according to an embodiment of the present invention.

2 is an enlarged view of part of FIG. 1 of the injection valve according to the first embodiment, in which the through-passage of the buffer chamber is formed by an axial groove and an annular groove provided in the nozzle spindle.

3 is an enlarged view, similar to FIG. 2, of an injection valve according to the second embodiment, in which the through-passage of the buffer chamber is configured as a longitudinal hole and a lateral hole provided in the nozzle spindle.

FIG. 4 is an enlarged view similar to FIG. 2 of an injection valve according to the third embodiment, in which the through-passage of the buffer chamber is configured as an annular gap between the wall of the hole of the intermediate disc and the nozzle spindle. It is a figure.

FIG. 5 has an additional storage chamber connected to the buffer chamber,
4 is a vertical cross-sectional view of an injection valve according to a modified example of FIG.

[Explanation of symbols]

1 valve body, 3 intermediate disc, 5 nozzle nut, 7
Valve holder, 9 guide hole, 11 valve member, 13
Sealing surface, 15 valve seat, 17 injection opening, 19
Pressure chamber, 21 pressure shoulder, 23 filter,
25 inflow passage, 27 connecting sleeve, 29
Chamber, 31 spring chamber, 33 valve spring, 35 bottom part,
39 nozzle spindle, 41 end face, 43 spring chamber, 45 disc, 47 sleeve, 49 valve spring, 51 pressure member, 53 end face, 55 stepped hole, 57 annular protrusion, 59 nozzle spindle 39
The first part of the nozzle spindle 39, the second part of the nozzle spindle 39, 63 buffer chamber, 65 end face, 67 axial groove, 69 annular groove, 71 edge, 73 longitudinal hole, 75 upper lateral hole, 77 bottom Side lateral hole, 79 annular gap, 81 storage chamber, H1
Front stroke, H3 maximum opening stroke

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Manfred Mack Federal Republic of Germany Altheim Hinter der Mauer 13

Claims (10)

[Claims] 1. A fuel injection valve for an internal combustion engine, comprising a valve member (11) slidable in an axial direction, the valve member (1).
1) is guided by the guide hole (9) of the valve body (1), and the valve body (1) is tightened to the valve holding body (7) via the intermediate disc (3), A chamber (29) for receiving two valve springs acting on the valve member (11) in the closing direction is provided in the valve holder (7), the first valve of the two valve springs being provided. The spring (33) always acts on the valve member (11) via the nozzle spindle (39), whereas the second valve spring (49) operates on the front stroke (H).
1), which acts on this valve member (11) after a predetermined opening stroke of the valve member (11), whereby the opening movement of the valve member (11) causes the first valve spring (3).
In a type adapted to be divided into a front stroke against the spring force of 3) and a remaining stroke against the spring force of the first and second valve springs (33, 49), The member (11) at least indirectly limits the fuel-filled buffer chamber (63), which during the opening stroke of the valve member (11).
The pressure created in the buffer chamber (63) causes the valve member (11) to
A fuel injection valve for an internal combustion engine, which acts against the opening stroke of the valve member (11) during the rest of the stroke. 2. The fuel injection valve according to claim 1, wherein the buffer chamber (63) is closed at the end of the front stroke of the valve member (11). 3. A valve member (11) at one end thereof,
An intermediate disc having a sealing surface (13) cooperating with a valve seat (15) provided on the valve body (1), and a buffer chamber (63) facing the valve body (1) side. End face side of (3) (6
5) and the end face (41) are formed at the end of the valve member (11) facing away from the sealing surface (13), at which end the valve member (11). 2. The fuel injection valve according to claim 1, wherein at least one nozzle spindle (39) of reduced diameter abuts against an end face (41) of the fuel injection valve. 4. A nozzle spindle (39) has a through-flow passage in the region (61) of a hole (55) formed in the intermediate disc (3) leading to this nozzle spindle (39), The through passage connects the buffer chamber (63) to the valve spring (3
3,49) which is connected to a fuel-filled chamber (29) provided in the valve holder (7), said buffer chamber (63) being closed after a predetermined opening stroke, The fuel injection valve according to claim 3. 5. A flow-through passage provided in a second part (61) of the nozzle spindle (39) is provided in this second part (6).
1) is formed by an axial groove (67) provided on the circumferential surface, and the end of the axial groove (67) facing the buffer chamber (63) side is the nozzle spindle (39). Second
Of the intermediate disc (3) after the end of the front stroke of the valve member (11). 5. Complete penetration into the interior and closure by this hole (55).
The fuel injection valve described. 6. A second part of the nozzle spindle (39)
The through-flow passage provided in (61) has one longitudinal hole (7
3) and two lateral holes intersecting this longitudinal hole (73), the upper lateral hole (75) of these two lateral holes being located in the chamber (29). Always open to the connected space, the lower lateral hole (77) opens into the buffer chamber (63) until the end of the front stroke of the valve member (11), 5. The fuel injection valve according to claim 4, which is closed by the wall of the hole (55) of the intermediate disc (3) during the rest of the stroke. 7. A hole (5) formed in the intermediate disc (3).
The annular edge formed in the entry opening on the buffer chamber side in 5) forms a first control edge, which first control edge is the second part (61) of the nozzle spindle (39). Cooperating with a second control edge formed on the edge of the lower lateral bore (77) provided in the edge facing the valve member (11), in this case the first control edge. 7. The distance from the second control edge is such that when the valve member (11) abuts the valve seat (15), the time when the buffer chamber (63) is closed is adjusted. Fuel injection valve. 8. The through-flow passage comprises a nozzle spindle (39).
An annular gap (79) between the peripheral surface of the second part (61) of the and the wall of the hole (55) provided in the intermediate disc (3).
And the annular gap (79) is
The fuel flow is prevented from flowing out of the buffer chamber (63) by a throttling action in the annular gap (79) after a predetermined increase in pressure in the buffer chamber (63).
The fuel injection valve described. 9. A buffer chamber (63) is connected to a storage chamber (81), said storage chamber (81) being advantageously valve body (1).
9. The fuel injection valve according to claim 8, which is formed by a blind hole formed in the intermediate disc (3). 10. A nozzle spindle (39) is composed of two parts, said nozzle spindle (39).
Inside the chamber (29) of the valve retainer (7), the part (61) having a through passage being guided in the hole (55) of the intermediate disc (3) forms the second part. A portion (59) which rushes into and which has the spring bearings (37, 51) of the valve springs (33, 49) forms a first portion, which first portion is the first valve spring. The fuel valve according to claim 4, wherein the fuel valve is held in contact with the second portion by the preload force of (33).